Organometallics 2011, 30, 375–378 375
DOI: 10.1021/om1009928
Fast Synthesis of Hydrazine and Azo Derivatives by Oxidation
of Rare-Earth-Metal-Nitrogen Bonds
Lijun Zhang,*,† Jing Xia,† Qinghai Li,† Xihong Li,† and Shaowu Wang*,†,‡
†Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-
Based Materials, Institute of Organic Chemistry, School of Chemistry and Materials Science, Anhui Normal
University, Wuhu, Anhui 241000, People’s Republic of China, and State Key Laboratory of Organometallic
‡
Chemistry, Shanghai Institute of Organic Chemistry, Shanghai 200032, People’s Republic of China
Received October 19, 2010
Summary: A novel N-N coupling reaction was developed
through the oxidation of rare-earth-metal-nitrogen bonds
produced by treatment of the easily available rare-earth-metal
amides [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 with aromatic primary
or secondary amines. The reaction provides the symmetrical
or unsymmetrical azo compounds and hydrazine derivatives
in good to high yields within a very short time under mild
conditions.
which can be applied as drugs, pharmaceuticals, agrochemicals,
and dyes in industries or precursors in organic synthesis.8
However, until now only a very limited number of methods
have been devised for the synthesis of hydrazine derivatives.
Alkylation of hydrazines has become the most frequently
used method.9 Almost all these transformations originating
from hydrazine demand several steps (protection and deprotec-
tion) for obtaining the required products.10 On the other
hand, some methodologies for azobenzenes were obtained:
(i) oxidation of aromatic primary amines;11 (ii) reduction of
nitro-aromatic compounds;12 (iii) coupling of primary aryl-
amines with nitroso compounds (Mills reaction); (iv) elec-
trophilic reactions of diazonium salts;13 (v) oxidation of
hydrazo derivatives; (vi) reduction of azoxybenzene deriva-
tives.8c However, long reaction time (10 h to 3 days)14 and
generally low chemical selectivity with many byproducts
leave some space for these methods to be improved. It was
reported that aromatic azo compounds could be synthesized
from anilines catalyzed by expensive gold nanoparticles
using O2 (3-5 bar) as an oxidant at 100 °C.15 Very recently
Jiao and co-workers developed the inexpensive catalyst
CuBr/pyridine to prepare symmetric and unsymmetric azo
compounds.16 Though new advances have been made, the
long reaction time is still a challenge to be improved. Most
important of all, until now, the direct synthesis of hydrazine
derivatives starting from the easily available secondary
Recently, various metal-initiated coupling reactions have
emerged as promising synthetic reactions. Much progress
has been made on the C-X (X = C, N, O, S) coupling
reactions1 initiated by such metals as palladium,2 copper,3
ruthenium,4 silver,5 and rare-earth-metal complexes.6,7
However, N-N coupling reactions initiated by metal com-
plexes still present a challenge.
The N-N coupling reaction provides a useful strategy for
the preparation of hydrazine derivatives and azo compounds,
*To whom correspondence should be addressed. E-mail: zljun@mail.
ahnu.edu.cn (L. Zhang); swwang@mail.ahnu.edu.cn (S. Wang).
(1) de Meijere, A., Diederich, F., Eds. Metal Catalyzed Cross-Cou-
pling Reactions, 2nd ed.; Wiley-VCH: Chichester, U.K., 2004; Vols. 1 and 2.
(2) For selected reviews on palladium-initiated coupling reactions,
see: (a) Yin, L.; Liebscher, J. Chem. Rev. 2007, 107, 133. (b) Slagt, V. F.; de
Vries, A. M.; de Vries, J. G.; Kellogg, R. M. Org. Process Res. Dev. 2010,
14, 30. (c) Yang, Y.; Cheng, K.; Zhang, Y. Org. Lett. 2009, 11, 5606. (d)
Kogan, V.; Aizenshtat, Z.; Popovitz-Biro, R.; Neumann, R. Org. Lett. 2002,
4, 3529.
(3) For selected reviews on copper-initiated coupling reactions, see:
(a) Evano, G.; Blanchard, N.; Toumi, M. Chem. Rev. 2008, 108, 3054. (b)
Tye, J. W.; Weng, Z.; Johns, A. M.; Incarvito, C. D.; Hartwig, J. F. J. Am.
Chem. Soc. 2008, 130, 9971. (c) Hamada, T.; Ye, X.; Stahl, S. S. J. Am.
Chem. Soc. 2008, 130, 833.
(4) For selected reviews on copper-initiated coupling reactions, see:
(a) Denichoux, A.; Fukuyama, T.; Doi, T.; Horiguchi, J.; Ryu, I. Org.
Lett. 2010, 12, 1. (b) Yi, C. S.; Lee, D W. Organometallics 2010, 29, 1883.
(c) Gao, R.; Yi, C. S. J. Org. Chem. 2010, 75, 3144. (d) Yi, C. S.; Lee, D W.
Organometallics 2009, 28, 4266.
(9) (a) Arterburn, J. B.; Rao, K. V.; Ramdas, R.; Dible, B. R. Org.
Lett. 2001, 3, 1351. (b) Brown, M. J.; Clarkson, G. J.; Fox, D. J.; Inglis,
G. G.; Shipman, M. Tetrahedron Lett. 2010, 51, 382. (c) Bredihhin, A.;
€
Groth, U. M.; Maeorg, U. Org. Lett. 2007, 9, 4975.
(10) Dey, S. K.; Lightner, D. A. J. Org. Chem. 2007, 72, 9395.
(11) For selected reviews on synthesis of azobenzene through oxida-
tion of aromatic primary amines, see: (a) Corma, A.; Serna, P. Science
2006, 313, 332. (b) Li, S.-C.; Diebold, U. J. Am. Chem. Soc. 2010, 132, 64.
(c) Goldstein, S. L.; McNelis, E. J. Org. Chem. 1973, 38, 183. (d) Huang, H.;
Sommerfeld, D.; Dunn, B. C.; Lloyd, C. R.; Eyring, E. M. Dalton Trans.
2001, 1301. (e) Farhadi, S.; Zaringhadam, P.; Sahamieh, R. Z. Acta Chim.
Slov. 2007, 54, 647. (f) Lu, W.; Xi, C. Tetrahedron Lett. 2008, 49, 4011. (g)
Biradar, A. V.; Kotbagi, T. V.; Dongare, M. K.; Umbarkar, S. B. Tetrahedron
Lett. 2008, 49, 3616. (h) Launay, J. P.; Tourrel-Paggis, M.; Lipskier, J. F.;
Marvaud, V.; Joachim, C. Inorg. Chem. 1991, 30, 1033. (i) Lim, Y. K.; Lee,
K. S.; Cho, C. G. Org. Lett. 2003, 5, 979.
(5) Weibel, J.-M.; Blanc, A.; Pale, P. Chem. Rev. 2008, 108, 3149.
€
(6) (a) Muler, T. E.; Hultzsch, K. C.; Yus, M.; Foubelo, F.; Tada, M.
Chem. Rev. 2008, 108, 3795–3892. (b) Amin, S. B.; Marks, T. J. Angew.
Chem., Int. Ed. 2008, 47, 2006–2025. (c) Chen, E. Y.-X. Chem. Rev. 2009,
109, 5157and references therein.
(7) (a) Komeyama, K.; Sasayama, D.; Kawabata, T.; Takehira, K.;
Takaki, K. J. Org. Chem. 2005, 70, 10679. (b) Hou, Z.; Fujita, A.; Zhang,
Y.; Miyano, T.; Yamazaki, H.; Wakatsuki, Y. J. Am. Chem. Soc. 1998, 120,
754. (c) Zhang, W. -X.; Nishiura, M.; Hou, Z. Angew. Chem., Int. Ed. 2008,
47, 9700. (d) Zhang, W.-X.; Nishiura, M.; Hou, Z. J. Am. Chem. Soc. 2005,
127, 16788. (e) Cornehl, H.; Hornung, G.; Schwarz, H. J. Am. Chem. Soc.
1996, 118, 9960.
(12) (a) Biradar, A. V.; Kotbagi, T. V.; Dongare, M. K.; Umbarkar,
S. B. Tetrahedron Lett. 2008, 49, 1828. (b) Srinivasa, G. R.; Abiraj, K.;
Gowda, D. C. Tetrahedron Lett. 2003, 44, 5835.
ꢀ
ꢀ
ꢁ
ꢂ
ꢁ
ꢁꢀ
(13) (a) Prikryl, J.; Cerny, M.; Belohlavova, H.; Machacek, V.;
ꢀ
Lycka, A. Dyes Pigm. 2007, 72, 392. (b) Mijin, D. Z.; Baghbanzadeh,
€
(8) (a) Bredihhin, A.; Groth, U. M.; Maeorg, U. Org. Lett. 2007, 9,
M.; Reidlinger, C.; Kappe, C. O. Dyes Pigm. 2010, 85, 73.
(14) Reuter, R.; Hostettler, N.; Neuburger, M.; Wegner, H. A. Eur. J.
Org. Chem. 2009, 5647.
€
1097. (b) Bredihhin, A.; Maeorg, U. Tetrahedron 2008, 64, 6788. (c) Hamon,
F.; Djedaini-Pilard, F.; Barbot, F.; Len, C. Tetrahedron 2009, 65, 10105. (d)
Iranpoor, N.; Firouzabadi, H.; Khalili, D.; Motevalli, S. J. Org. Chem. 2008,
73, 4882. (e) But, T. Y. S.; Toy, P. H. J. Am. Chem. Soc. 2006, 128, 9636.
´
(15) Grirrane, A.; Corma, A.; Garcıa, H. Science 2008, 322, 1661.
(16) Zhang, C.; Jiao, N. Angew. Chem., Int. Ed. 2010, 49, 6174.
r
2011 American Chemical Society
Published on Web 01/11/2011
pubs.acs.org/Organometallics